1. Field of the Invention
The present invention relates to material spraying devices and more particularly pertains to such a device that is hand-held, portable and easy to use.
2. General Background and State of the Art
The use of spraying devices a wide variety of projects is known in the prior art. Such sprayers may be used to spray liquids, chemicals, aggregate, or other compounds. It is recognized that there are generally three types of sprayers; 1) hand-held manually powered units; 2) air compressor powered units; and 3) motorized units which may have a mechanical mixing tank. The present invention is of the hand-held manually-powered type, sometimes referred to as a “bug sprayer.” Some of the better-known devices that are of some relevance to the present invention will be described here.
U.S. Pat. No. 4,364,521 to Stankowitz discloses a portable, self-contained texture applicator having a pressure tank adapted to be charged from an external source or by a manually actuatable pump incorporated in the tank. Air pressure can only be released by the spraying operation. Stankowitz does not disclose the use of a portable hand-held, manually-powered, low pressure sprayer with an air control valve.
U.S. Pat. No. 4,204,645 to Hopp discloses a hand-held, compression-type sprayer. Air pressure can only be released by the spraying operation. Hopp does not disclose the use of a portable hand-held, low pressure sprayer with an air control valve.
U.S. Pat. No. 3,820,722 to Jett, et al., discloses a portable hand-held aggregate sprayer that is manually pressurized. The aggregate is sprayed most effectively after significant pressure is manually built up in the device by the user. Air pressure can only be released by the spraying operation. Jett, et al. does not disclose the use of a portable hand-held, low pressure sprayer with an air control valve.
U.S. Pat. No. 3,002,699 to Pinke discloses a manually-operated sprayer having an air pump and a receptacle attached to it that contains the material to be sprayed. Air pressure can only be released by the spraying operation. Pinke does not disclose the use of a portable, hand-held, low pressure sprayer with an air control valve.
None of the above patents, taken either singly or in combination, is seen to describe the present invention as disclosed and claimed.
While portable, hand-held, manually operated sprayers are known, there are several disadvantages to the known devices.
Prior art devices require the individual to provide substantial force and repeated pumping action to begin the spraying operation, and not all individuals are capable of providing or sustaining such force for any appreciable length of time.
The requirement inherent in prior art devices for the application of substantial force in the pumping action by an individual also leads to heating up and excessive wear on vital parts of the sprayer, such as the seals on the extremis of the piston rod.
In the prior art devices, as the level of the material being sprayed in the container is lowered during the spraying operation, the amount of applied operating force required is lessened, but the material consistency of the spray is substantially lessened and the sprayed material is generally wasted as the air is gradually forced out through the spray nozzle.
There is no portable sprayer that provides for operation with lower applied pressure, thus enabling longer operation and more effective operation, that also provides a control device that reduces wastage of the material being sprayed.